Does An “Acidic Body” Cause Or Worsen Cancer?

I was asked recently if it’s important to prevent the body from being “too acidic,” for someone who has cancer. This topic has come up again and again over the nearly two decades during which I’ve worked in the cancer nutrition field. Given how common this belief is, it’s certainly worth discussing. It’s no surprise that there have been many studies completed in search for a connection between cancer and whether or not it can be prevented or slowed by eating an alkaline diet.

Does an “acidic body” cause cancer?

There is a significant contingent of the complementary, alternative, and integrative medicine communities that believes keeping the body “alkaline,” or less acidic, is one of the key factors for optimal disease prevention. There also is a belief that an “acidic environment favors cancer.” This belief likely arose from the fact that cancer cells, with their unusual, extremely rapid metabolic activities, tend to make the micro-environment in and around, a tumor more acidic. However, this acidic tumor micro-environment does not appear to measurably shift total body pH to be more acidic.

Further, there is no evidence that making the body itself more alkaline will have any affect on the acidity of the tumor. So, the observation that tumors are acidic may have led some people to conclude (mistakenly) that acidic environments cause tumors. In reality, it is tumors that cause acidic environments. Thus far, research simply does not support that a large focus on shifting total body pH to be more alkaline will improve cancer outcomes. Perhaps future studies will show some benefit of “being more alkaline”, but for now, that research does not exist.

Cachexia and body acidity

As an aside, it’s important to note that in later stages of cancer, when a person has significant metastatic disease – tumors that have spread throughout the body – the body can become acidic. However, this is not related to the tumor acidity itself. In advanced cancer, a condition called cachexia can occur.

Cachexia causes the body to inappropriately use lean tissue, such as muscle, for energy, and to fail to use fat and carbohydrates – the more appropriate sources of fuel (calories). This causes wasting and weakness, and can increase body acidity. However, this cannot be reversed with diet alone, and making the body more alkaline will not stop cancer cachexia from occurring in advanced cancer cases.

How do you measure acidity?

The other problem we face is how to measure acidity. Urine acidity, which is a test that many alternative medicine practitioners use to convince people to take “alkalinizing supplements,” is very “short term” and reactive. A change in what you put in your mouth can immediately, and drastically alter urine pH within hours. But we don’t know if this means that what you put in your mouth has done much to your blood and body’s pH levels over the long term. One short-term study (one week) demonstrated urine and blood pH could be increased with an alkaline mineral supplement, but even these study authors concluded that they had no idea if this had any implications for long-term health.

In the end, most agree that diet can nudge blood and body pH. For how long, and to what effect, isn’t clear in the majority of cases.

It is important to note though, that while body acidity can be altered by general diet patterns (more on that below), these changes are very small. A pH of 7 is neutral. Above pH 7 is alkaline, and below 7 is acidic. Blood pH is naturally, slightly alkaline. Healthy blood pH levels range from approximately 7.35 to 7.45.

What if you could shift your body pH?

The body fights VERY hard to keep blood pH in that range, and it’s controlled mainly by the kidneys and by the respiratory system. If the body becomes too acidic (acidosis) or too alkaline (alkalosis) it’s due to either respiratory or metabolic causes. These very serious medical conditions are referred to as metabolic or respiratory acidosis, and metabolic or respiratory alkalosis. Regardless of the hows and whys, if a person’s blood pH varies much from the normal 7.35 to 7.45 range, that person is in big trouble, medically speaking. And what their urine pH is doing isn’t a big part of the equation.

In the end, you cannot push blood or total body pH very hard in either direction with diet alone. The body simply recalibrates, to bring it back to baseline. And what that baseline is may vary from person to person, within that narrow range of approximately 7.35-7.45.

The bottom line

Eating fruit and vegetables is linked with lower risk of all kinds of chronic diseases, including some types of cancer. Most fruit and vegetables are “alkalinizing,” but does this play much of a role in why these foods tend to be protective against chronic disease? We don’t know. It may play some role, but so do phytochemicals, vitamins, minerals, fiber, and the thousands of disease-fighting components found in plants.